This study incorporates the steer axis moments equation into the vehicle dynamics in order to analyze the vehicle’s straight driving deviations. These moment equations are produced by wheel alignment angularities which are toe, camber, caster, king-pin inclination and oblique integral rear axle angle. And the influence factors of the vehicle’s straight driving deviations are toe, caster, camber and king-pin inclination in sequence. And then find out the solution of different wheel alignment angularity formula for reduce the vehicle’s straight driving deviation. After practice the examples of vehicle design revision and impact adjustment, the formulas this study proposed can not only satisfy the specification, but also reduce the problem of vehicle’s straight driving deviations.